Lemma 2.4 (Lemma 4.1 [1]}) 

Suppose \(\triangle _E ABC\)  is a Euclidean triangle with the edge lengths \(a,b,c\) .
If all the inner angles in \(\triangle _E ABC\)  are at least \(\epsilon >0\) , then
\(\frac{\epsilon }{8} a^2\le |\triangle _E ABC|\le \frac{1}{\epsilon }a^2.\) 

